The lookup method returns the value at the specified path in the JSON object.
NOTE: This method does not make a copy of the value, so modifying the returned value affects the original object.
lookup( pathElements )
| Argument | Description |
|---|---|
pathElements
|
(json_path_string_or_integer) The path of the value to return. Specify one or more path elements, which might be object attribute names (strings) or array indexes (integers). |
(LuaJsonValue) Returns the value that exists at the specified path, or nil if the specified path does not exist.
myJsonObject = LuaJsonObject:new()
myJsonObject:assign( {
attr1=LuaJsonObject:new( { n=42, x=5 } ),
attr2=LuaJsonArray:new( 1, 2, "three" ),
} )
print ( myJsonObject:lookup("attr2",2):value() )
-- three (LuaJsonArrays are zero-indexed)
-- Modifying the returned value changes the original object
local lookup_attr = myJsonObject:lookup("attr1"):object()
lookup_attr:assign("y",3)
print (myJsonObject:string())
-- {"attr1":{"n":42,"x":5,"y":3},"attr2":[1,2,"three"]}